Recently, solar photovoltaic systems have been provided that perform solar photovoltaic using solar cell modules that are arranged in a matrix on a roof of a building or the like. Such solar photovoltaic systems use solar cell module terminal boxes in order to electrically connect adjacent solar cell modules and extract electrical power generated by the solar cell modules.
A terminal box is attached to the rear face side of a solar cell module in which a large number of solar cells connected in series are arranged. As disclosed in, for example, PTLS 1 and 2, a terminal box is configured such that a plurality of terminal plates are arranged in a box main body and a bypass diode is disposed between adjacent terminal plates.
This sort of box main body is made of a synthetic resin material and in the shape of an open-topped box. Furthermore, an opening portion is formed on a bottom face of the box main body throughout substantially the entire width of the bottom face. The plurality of terminal plates inside the box main body are arranged such that their tip ends face the opening portion of the box main body. An output lead wire connected to each solar cell group of the solar cell module passes through this opening portion. Each output lead wire that passes through the opening portion is connected by soldering or the like to the tip end of a corresponding terminal plate.
The box main body is connected to the solar cell module in this manner, and is internally filled with an insulating resin such as silicone resin. Accordingly, components such as terminal plates and output lead wires inside the box main body are sealed. Furthermore, the box main body is hermetically sealed with a cover attached to the open top of the box main body.